This invention relates generally to connectors, and in particular, to a high frequency edge mount launch connector for transitioning coaxial to planar microwave signals.
High frequency edge mount launch connectors may be used to transition high frequency signals from coaxial to planar transmission line structures. High frequency signals include signals which are greater than 500 megahertz and extend up through the K-band, such as microwave signals. Applications which require the use of high frequency signals require unique connectors and circuit boards. Examples of some of these applications include cellular and pager linear power amplifiers, cellular handset filters, and DBS low-noise block down converters. High frequency signals typically consist of time varying electromagnetic fields which may be able to induce currents on metal surfaces.
In order to transition or “launch” high frequency signals from a cylindrically shaped coaxial cable to a planar circuit board signal trace, high frequency edge mount connectors may be used. In general, in-line edge mount connectors are preferred to “launch” the high frequency signals. One end of the edge mount connector is connected with a signal line which is used to carry a high frequency signal, such as a coaxial cable, while the other end of the edge mount connector includes a pin which extends from a housing of the connector. The pin is typically soldered to a signal trace of a circuit board in order to complete the connection and allow for a high frequency signal to travel down the signal line, through the edge mount connector, and to the circuit board. Additionally, the housing of the edge mount connector is connected with a ground located on the circuit board in order to complete the connection.
An accurate characterization of packaged high frequency circuits, such as Broadband MMIC power amplifiers, requires coaxial to planar transitions which have a low return loss. Therefore, as the wavelength of the high frequency signals decreases, the size of the pin on the edge mount connector needs to be reduced in order to minimize the return loss. Reducing the size of the pin, however, complicates the attachments of the pin to the signal trace of the circuit board. Since the pin is smaller, damage to the pin may occur if the pin is not handled properly when placed in contact with the signal trace. Additionally, aligning the pin on the signal trace is made more difficult when the pin is made smaller.
In addition to complicating the attachment of the pin to the circuit board, as the wavelength of the high frequency signals decreases, it becomes more difficult to achieve both low return loss and insertion loss when transitioning the high frequency signal from the signal line to the circuit board. For example, the high frequency signal becomes more sensitive to impedance mismatches between the edge mount connector and the circuit board.
It would be desirable to have an edge mount connector that is capable of “launching” high frequency signals from a cabled transmission signal line to a circuit board with a low return loss and insertion loss over a wide bandwidth, that has an in-line design which is more simple to fabricate, that allows for the a more accurate placement of the pin on a circuit board with reproducible results, that prevents damage to the pin, and that is adaptable to circuit board substrates of varying thicknesses.